Mallory bodies (MBs) are hepatocellular, filamentous aggregates associated with alcoholic liver disease and a number of other hepatic disorders. MB filaments are composed partly of prekeratin and are, therefore, related to normal intermediated (10 nm in diameter) filaments. Several lines of evidence suggest that MB formation is controlled or modulated by the cellular microtubular system. For example, conditions that are known to cause breakdown of cellular microtubules promote marked increases in the concentration of intermediate filaments. In the proposed project, we will investigate temporal aspects of MB biogenesis with particular emphasis on microtubular involvement. These studies will utilize the griseofulvin-mouse model, a dynamic system in which the appearance or disappearance or disappearance of MBs can be induced by administration or withdrawal of the antibiotic, respectively. MBs, prekeratin (bovine hoof), and tubulin (rat brain) will be prepared, injected into guinea pigs, and high-titre, specific antisera obtained. These cytoskeletal components will be monitored during griseofulvin administration. Intact structures (filaments, microtubules) will be visualized using indirect immunoperoxidase labeling of cryostat sections. Since MBs are not seen in the liver for approximately four weeks into the griseofulvin feeding, we will explore the possibility that non-aggregated MB components are present during this period. Soluble, immunoreactive material will be measured in the cytosol fraction using appropriate enzyme-immunoassays. We will examine both MB induction and disappearance. Moreover, induction in "primed" systems (mice fed griseofulvin, then removed from the substance) by colchicine and ethanol will be studied. In addition, we will examine the effect of long term ethanol administration on the hepatic cytoskeletal system. By monitoring both MBs and microtubules concurrently during induction of MBs, the relationship between these two structures should be clarified. Results obtained during the proposed project should either strengthen or weaken the "antimicrotubular" hypothesis of MB formation in alcoholic liver disease.